19873连通块中点的数量

19873连通块中点的数量

⭐️难度：中等
🌟考点：连通块、并查集
📖

📚

package test;

import java.util.Scanner;

public class Main {
    static int N = 100010;
    static int[] a = new int[N];
    static int[] p = new int[N];
    static int[] size = new int[N];
    static int n;
    static int m;

    // 路径优化
    static int find(int x) {
        return p[x] == x ? x : (p[x] = find(p[x]));
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();
        m = sc.nextInt();

        // 初始化并查集
        for (int i = 1; i <= n; i++) {
            a[i] = i;
            p[i] = i; // 每个点的父节点初始化为自身
            size[i] = 1;
        }

        for (int i = 1; i <= m; i++) {
            String op = sc.next();
            if (op.equals("C")) {
                int x = sc.nextInt();
                int y = sc.nextInt();
                int px = find(x);
                int py = find(y);
                if (px != py) {
                    size[py] += size[px]; // 先更新 size 数组
                    p[px] = py; // 再合并
                }
            } else if (op.equals("Q1")) {
                int x = sc.nextInt();
                int y = sc.nextInt();
                if (find(x) == find(y)) {
                    System.out.println("Yes");
                } else {
                    System.out.println("No");
                }
            } else {
                int x = sc.nextInt();
                System.out.println(size[find(x)]);
            }
        }
    }
}